Spark plug



Dec. 18 1923;

SPARK PLUG M. P. SULLIVAN Filed May 20, 1920 INVENTOR Mddf/Ze? l. Sal/Mm87 W a? A T ORA/E Patented Dec. 18, 1923.

-UNITED STATES j 1,477,784 PATENT OFFICE.

' IAUBICE P. SULLIVAN, OI NEWARK, NEW JERSEY, ASSIGIiTOB '10 SPLITDORIELEC- 'I'BICAL COKIAHY, OI NEWARK, JERSEY.

sraax PLUG.

Application filed Kay 20,

To all whom it may concern-.- a Be it known that I, MAURICE P. SULLIVAN,a citizen of the United States, residing at Newark, in the county ofEssex, State of New Jersey, have invented certain new and usefullmprovements in a Spark Plu of'which the following is a descrlption, reerence bein had to the accompanying drawing an to the figures ofreference In marked thereon.

My invention relates to a spark plug more particularly of thenon-grounded type, that is to say, one in which both the electrodes areinsulated and brou ht out flosuitable connecting devices. Suc plugs areuseful in so-called two-s ark ignition systems, that is to say, where51cm are two sparks in series in one cylinder. For such purposes it iscommon practice to use one plu in which 2 both terminals are insulated,suc as in the plug shown and described herein, and a second plug of theusual ty wherein only one electrode is insulated, 0 other being theshell of the plu or the engine itself.

:5 One of the o jects of my invention is to provide a plug of the abovetypewhich is rigid in construction and relatively cheap to manufacture.

M invention is set forth in a single figure 80 of the attached drawing,which shows a sectional view through various arts of the plug, exce tthe central electro e.

In the rawin 1 is a nut corresponding to the usual shel having threads 2at one end for the purpose of screwing the plug into an engine cylinder.The central hole through the nut 1 carries a tube shaped. insulator 3,preferably of wound mica, thelower end of which rests against a head 4of the sleeve electrode 5, the interior of which is preferably bored totaper to take a tapered central electrode 6, which is insulated from theinterior wall of the sleeve 5 by an insulator 7, preferably of woundmica. The insulator 7 referably extends at its lower end flush wit thehead 4 leaving an annular space 8 around the sparking terminal 9 whichis fastened to the central electrode 6. The head 4 has fastened theretoa sparking terminal 10'which is formed to co-operate with the terminal9. Positioned over the tube insulator 3 at its lower end and resting onthe head 4 is a rin insulator 11, which is preferably made u o a seriesof mica washle ors 12, one of which only is'indicated, the

. v l 1920. Serial No. 882,781.

understood of course that the insulators 11 and 13 may be of one piecematerial of any other suitable kind. It is to be noted that theinsulators 11 and 13 rest against opposite faces of the nut 13 therebyholding it in longitudinal position on the tube insulator 3. Resting onthe insulator 13 and making contact with the sleeve 5 at 15 is aconnecting terminal ring 16 having terminal stud 17 securely fastenedthereto .and a nut 18 on the stud 17 for connecting the ignition wirethereto. .Positioned over, the u per end of the insulator 7 and thecentral 0 ectrode 6 is another insulator 19 which engages the connectingring 16. The insulator 19 is preferably made up of a series of mica rinone of which is shown at 20 and the was er 21 rests on the; rin 1 9 anda clamping nut 22 engaging threa s 23 on the upper end of the centralelectrode 6, draws the same securely within the electrode sleeve 5 andthrough the medium of the head 4 all of the'parts are clamped securelyto the nut or shell 1. The terminal nut 24 being used to secure anyterminal that may be used between it andthe clamping nut 22.

Havin thus described my invention what I c aim is:

1. In a spark plug, a one piece shell adapted to be screwed into anenglne cylinder, said shell carrying a tube shaped insulator within itscentral opening and a ring of insulating material over the ends of thetube and immediately adjacent both ends of the shell, a metallicelectrode sleeve within said tube insulator and having a head forengaging the lower of said ring insulators and a sparking terminalfastened to the head, said sleeve also having a tapered hole passingtherethrou h, a tapered central electrode pin fitted within the taperedhole but insulated from said sleeve and having a sparking terminal,spaced away from said pin insulator, a terminal connecting ring seatedon the upper of said insulating rin and in annular engagement withsaidmeta lic sleeve, an, insulator positioned over-the central in andresting on said connecting ring an means engaging the outer end of the!central pin to draw and hold together all of said parts.

2. In a non-grounded spark plug, a nut threaded at one end for screwinginto an engine cylinder, said nut carrying; two conccntrically arrangedelectrodes, one within the other but insulated one from the other andfrom the nut, and two spacing insulators engaging the nut 011 oppositefaces, said outer electrode having a relatively thick tapering head; aterminal connecting ring in electrical engagement with the outer of saidelectrodes and resting on the upper of said spacing insulators, aninsulator above said ring, the inner surface of said outer electrode aswell as the inner electrode being tapered,

and means on the outer extremity of the inner electrode for drawing saidtapered portions into normal 0 erative position, the insulator betweensaid concentrically arranged electrodes extending substantially fiushwith In testimony 'whereof, I afiix my signature.

MAURICE P. SULLIVANw

